I mistakenly installed a version of Ad Block for Netscape 7.0 into Netscape 7.1. I got the message, "install successful". The only change I have experienced is that now, I cannot open Mail/News without it causing NS 7.1 to crash.

How do I fix this mess? I do have a tape drive with a pre-install backup of all the NS 7.1 files. Should I attempt a rollback, by overwriting the folder and profile folder with the backed-up files? Or, is there an easier solution.

I fixed the problem by editing prefs.js. Actually the culprit turned out to be not from Adblock. I had previously added mnenhy a mail header editor. There were some ill-formed user_pref strings generated by this "utility".

I just commented out the bad entry, and will eventually delete it. It just goes to show that sometimes it's not the last thing you installed, but the next to last that you thought was stable.